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Q: Stalling battery

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I am trying to start my car but I am hearing a rap. Also when I check the battery there are small bubbles forming. Is my battery completely dead or just very depleted
My car has an automatic transmission.

Hi There, What you are describing sounds like you may have a voltage regulator that is allowing the alternator to supply too much power to the battery. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. You may also smell a bit of smoke due to things potentially getting too hot. I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

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